Suspended ceiling



Jan..27.,1970 I .J. FISCHER 3,491,500

SUSPENDED CEILING Filed Feb. 21, 1968 2 Sheets-She et 1 FEGA INVENTOR Jam. 27, 1970 J. FISCHER 3,491,500

SUSPENDED CEILING Filed Feb. 21, 1968 2 Sheets-Sheet z United States Patent 3,491,500 SUSPENDED CEILING Jean Fischer, Skt. Klemens, Fyn, Denmark, assignor t0 Daempa A/S (Det Fyenske Traelastkompagni A/S),

Knarreborg, Denmark, a company of Denmark Filed Feb. 21, 1968, Ser. No. 707,144 Claims priority, application Denmark, Feb. 22, 1967, 960/67 Int. Cl. E04b 5/57 US. Cl. 52-484 3 Claims ABSTRACT OF THE DISCLOSURE The invention relates to a suspended ceiling of the type comprising rectangular pans or ceiling plates arranged in series and carried by rails suspended from the main ceiling. The opposite edges of each plate rest on the uppersurfaces of adjacent carrying rails and have downwardly directed projections, such as tongues or channels, engaging into complementary slots in said rails, and along the other pair of opposite edges each plate comprises a pair of upstanding flanges forming an angle slightly greater than 90 with the main portion of the plate and acting as cooperating spacers between adjacent plates.

The present invention relates to a suspended ceiling composed of rectangular plates which along two opposite edges are supported on parallel carrying rails hung up in the ceiling and along the two other sides are provided with upwards-turned stiffening flanges.

Such extra ceilings may have as their sole purpose to cover the main ceiling and installations, if any, mounted under the latter, but if it be desired, other aims may be gained, as the suspended ceiling may for example have a sound-controlling effect on the premises or may be incorporated in a heating or ventilation plant for the latter.

Such ceilings are known in numerous embodiments and at highly different prices. A not quite negligible part of the total costs is spent on the mounting, and a particularly easy and rapid mounting is therefore aimed at, particularly when it be desired to get a low-priced suspended ceiling. With a view to this, the face proper of the ceiling may consist of comparatively large plates which measure for example 120 by 60 cm. and which are placed on the carrying rails which are often constituted by T-irons, the webs of which are directed upwards towards the main ceiling. The plates may with their ends rest loosely on the flanges of the T-irons, or the latter may engage grooves in the ends of the plates When a safer securing of the plates and a more or less concealed mounting of the carrying rails are desired, but in practice it will, however, be impossible without a direct connection between the stiffening flanges of the ceiling plates to achieve so tight transverse joints between the latter that the joints will become so to speak invisible. For this reason the plates are often chamfered along their longitudinal edges to conceal irregularities at the joints, e.g. deriving from inaccurate manufacture of the plates or from the sagging of the plates between the carrying rails.

An object of the invention is to provide a suspended ceiling which consists of rectangular plates and associated carrying rails and which is particularly cehap to manufacture, transport and mount, and in which a kind of interlocking between the plates and the carrying rails is achieved and thereby a good fixation of the plates in relation to each other without a direct interlocking of the stiffening flanges of two neighbouring plates being required for this purpose and no separate locking members, either, between the plates and the carrying rails as is the case in more expensive, high-quality ceilings, where great ice stress is put on the appearance of the ceiling when mounted.

The characteristic feature of the suspended ceiling according to the invention is that the stiffening flanges extend upwards at an angle of slightly more than to the plate, and that at the ends of the flange the plate is provided with downwards-directed projections engaging fixation slots in the upper sides of the carrying rails.

The flanges will in a manner known per se to a wide extent increase the bending strength of the plates, so that the sagging of the plates between the carrying rails can be kept within the limits permitted, even if the plates in themselves, e.g. due to a slight thickness, possess only a slight bending strength. At the same time the flanges act as a kind of spacers between the plates slid together in the longitudinal direction of the carrying rails, establishing a certain minimum spacing between the plate edges visible from below. This means that the finished ceiling will appear with distinct, regular joints between the successive plates, which as a rule must be considered more attractive esthetically than quite narrow joints, in which misalignments or other irregularities will be more pronounced. It may furthermore be pointed out that the upwards-directed flanges will together form a bottom at the top of the joints, so that no sifting-down from the main ceiling may occur through these joints. The advantages mentioned are gained without any direct assembling or clamping together of the mutually adjacent stiffening flanges which would make the construction more expensive and make it diflicult to mount the plates and particularly to remove them separately, e.g. for the inspection of an installation over the suspended ceiling. The fact is that the necessary holding together of the components of the ceiling is ensured by the fixation between the individual ceiling plates and their carrying rails, as the downwards-directed projections on the plates engage the rails with a locking effect, but are nevertheless easy to disengage in case of need, e.g. when it be desired to dismantle a single plate. During the mounting of the plates it is a further advantage that thanks to their engagement with the projections the carrying rails will be positively prevented from yielding laterally, so that the plate or the plates already mounted might drop down.

As regards the transport it is an advantage that neither the upwards-turned flanges nor the downwards-directed projections on the plates need prevent a close piling of the latter, particularly because the angle of the flanges to the plate proper is slightly over 90.

According to the invention it is to be preferred that the outermost edge portion of the stiffening flange is bent over so as to be at right angles to the plate. Hereby the width of the joint between two neighbouring plates is determined by surface abutment between the mutually adjacent flanges, so that height differences, if any, between the plates will be of no consequence.

The carrying rails may according to the invention expediently consist of sheet metal which is profiled into box-shape and the longitudinal edge portions of which form the upper side of the box profile and are terminated by inwardly bent lips for the formation of a fixation slot. These carrying rails will be fully visible in the finished ceiling, and regard must of course be paid to this fact at thev design and surface treatment of the carrying rails. The moulding of the rails may, however, be performed cheaply, e.g. in a section rolling mill, by which means the provision of the fixation slot will require no special operations. The resilience of the material can be utilized for ensuring such a clamping of the two lips that these will secure the inserted projections on the plates positively.

In another embodiment according to the invention the carrying rails consist of sheet metal which is profiled into box-shape with a central suspension web which projects from the upper side and is constituted by the longitudinal edge portions of the sheet metal and is located between two groove-shaped fixation slots for engaging complementarily shaped downwards-directed projections along the edges of the adjacent sheet metal plates of which the projections as well as with the upwards-turned stiffening flanges forrn integral portions. In this case there may in a convenient manner be ensured a balanced suspension of the carrying rails, e.g. by means of longitudinally adjustable carrying straps, the lower ends of which are connected to the suspension web of the box profile close to the upper edge thereof, and as each of the ceiling plates disposed on either side of the carrying rail has its own fixation slot in the upper side of the rail, the further advantage is gained that the projections of these plates lie quite clear of each other instead of engaging between each other in one and the same fixation slot.

The invention will in the following be further explained with reference to the accompanying drawings which are partly diagrammatical and in which FIG. 1 shows a perspective view of a section of the ceiling with parts of a total of four rectangular plates, two of which are for the sake of perspicuity shown without edge stiffening flanges,

FIG. 2 a section on line IIII in FIG. 1,

FIG. 3 a section corresponding to FIG. 2- and showing how a carrying rail can be hung up in the ceiling,

FIG. 4 a suspension plate shown in section in FIG, 3,

FIG. 5 another embodiment of the ceiling according to the invention shown in section transversely to a carrying rail, and

FIG. 6 a section at right angles to the section in FIG. 5 in a ceiling plate consisting throughout of metal.

The suspension ceiling in FIGS. 1-4 comprises a number of equidistant carrying rails 1 which in the embodiment shown consist of sheet metal forming a substantially closed box profile, there being, however, in the upper side 2 of the latter left a slot 3 between the longitudinal edges of the plate, the said edges forming inwardly bent-over slot lips 4. As shown in FIG. 3 there may for the suspension of the carryin rails 1 be used wire straps 5 with carrying plates 6, see also FIG. 4, from the material of which locking tongues 7 bent outwards to either side have been stamped out. Such a carrying plate 6 can from above he slid down into the longitudinal slot 3 of the rail, until the locking tongues 7 have passed the lips 4 and resile into the position shown in FIG. 3. When next the plate 6 is pulled back in relation to the carrying rail 1, the latter will be brought to rest on the two locking tongues 7.

The carrying rails 1 hung up in this manner serve as supports for rectangular ceiling plates 10' which for example may measure about 120 by 60 cm. and which are placed with their longitudinal sides at right angles to the carrying rails 1. Along these longitudinal sides or side edges the plates are provided with stiffening flanges or edge rails 11 forming an angle of slightly over 90 to a horizontal flange 12 which is secured to the plate 10 and is provided with downwards-directed projections in the form of end tongues 13, FIGS. 1 and 2, which engage beyond the end edge of the associated plate 10 and are pressed down into the fixation slot 3 of the carrying rail 1. As shown in FIG. 2, each tongue 13 may at its bottom comprise a bend or a thickening 14 which by engaging the edge of the associated lip 4 causes a certain locking effect.

As mentioned above, the stifiening flange 11 is tilted slightly outwards from the plate edge, but it terminates in an edge portion 15 which is at right angles to the plate 10. When two plates 10 disposed in the same row are slidtogether in the direction of the carrying rails, the said edge portions 15 will get surface abutment against each other 4 and will thereby ensure that between the plates 10 proper a joint 16 of a suitable width is left.

The flanges 11 and the tongues 13 may have such a bevel that these parts will permit a tight piling of a great number of ceiling plates 10 ready for being mounted.

In the embodiment shown in FIGS. 1 to 4 of the drawing it is taken for granted that the horizontal flange 12 is glued to the upper side of the plate 10 proper, but the connection between these components may also be ensured in some other way, e.g. by the flange 12 engaging into a corresponding groove in the plate edge. Certainly, this presumes a slightly increased thickness of plate, but on the other hand the fire resistance of the covering ceiling will then not be impaired by a glue connection.

While the ceiling plates 10 in FIG. 1 are provided with separately mounted edge rails with the flanges 11 and the tongues 13, FIGS. 5 and 6 show an embodiment with all metal ceiling plates 10 which along the two opposite longitudinal edges have bent-up stiffening flanges 11, 15 and along the two other opposite edges have downwards-directed projections 13 in the form of beads or grooves with upwardly diverging walls. These projections fit down into fixation slots 3 in the upper side of the carrying rail 1. As was the case with the embodiment described above, this carrying rail has box profile, but in FIG. 5 it is shown with two groove-shaped fixation slots 3 disposed on either side of a central, upwardly-directed suspension web 29 which may be provided with holes for a suitable number of carrying straps 5 secured in the ceiling.

What I claim is:

1. A suspended ceiling structure comprising a plurality of rectangular ceiling elements arranged in rows and which along two opposite edges perpendicular to the direction of the rows are provided with upstanding stiffening flanges and at their other opposite edges have downwardly directed projections, a plurality of carrying rails which are parallel to said other opposite edges of the ceiling elements and each comprising a strip of sheet metal that is formed into a box profile having an upper element-supporting face presenting upwardly open groove means in which said downwardly directed projections of the adjacent edges of two rows of ceiling elements are received, and carrying rail suspending means extending upwardly from said box profile and between said rows of ceiling elements.

2. A structure as claimed in claim 1, wherein the longitudinal edge portions of said strip of sheet metal constitute said upper element-supporting face of the box profile and terminate in inwardly bent-over lips which together form a central upwardly open groove which constitutes said groove means.

3. A structure as claimed in claim 1, wherein the longitudinal edge portions of said strip of sheet metal form a central suspension web projecting from said upper elementsupporting face of the box profile between two upwardly open grooves which constitute said groove means.

FOREIGN PATENTS 219,815 1959 Australia. 843,942 1960 Great Britain. 880,226 1961 Great Britain.

, JOHN E. MURTAGH, Primary Examiner US. Cl. X.R. 52495 

